Educational device.



APPLICATION FILED DEO.2, 1905.

PATENTED OCT. 9, 41906.

Afro/mns i nor. DrivID MIroHELL,

or SANDUSKY, orne.-

EDUCATIONAL DEVICE.

Speccation of Letters Patent.

,Patented oct. e, ieee.

vApplication iled December 2, 1905. Serial No. 289,954.

To all whom it may concern:

Beit known that LROY DAVID MITCHELL, a citizen of the United States, and a resident of Sandusky, in the county of Erie and State of Ohio, have invented a new and Improved Educational Device, of which the following is a full, clear, and exact description.

The purpose of the invention is to provide a simple device to assist a teacher in instructing a class in mathematics, particularly in addition, which device will save the time of a teacher in dictating problems and the time of the students in writing them, it being possible for the teacher to quickly and accurately designate the boundaries of figures on a chart in columns, the figures within which columns are to be added, and for the students to locate and rule off the boundaries without injury to the chart.

A further purpose of the invention is to provide a device of the character described which will be very simple, easily understood, and readily handled, and which can be con# veniently held in the lap or placed flat upon a Idesk.

The invention consists in the novel construction and combination of the several parts, as will be hereinafter fully set forth, and pointed out in the claims.V

Reference is to be had to the accompanying drawings, forming apart of this specification, in' which similar characters'of reference indicate corresponding parts in all the figures.

Figure 1 is a plan view of the limproved device. Fig. 2 is a longitudinal section taken practically on the line? 2 of Fig.l 1. Fig. 3 is a perspective view of one of the adjustable deining-arms employed, and Fig. 4 is a longitudinal section through one of the slides.

A represents a frame comprising a bottom member 10, a top member 11, and side members 12 and 13, and within this frame a chart B is located, held in place by a suitable back- B', secured by clamps B2 or their equivalents, as shown in Fig. 2. This chart B iS ruled in a series of columns, and each column contains a series of single figures arranged one below the other, the figures on the ch/art being in alinement both vertically and transversely.A l.

The iigures in the columns of theV body portion of the chart are promiscuously arranged; but at the upper edge of the chart adjacent to the inner edge of the upper member 11 of the frame a horizontal definingcolumn 14 is producedldivided into vertical columns corresponding to the body-columns on the chart and reading therewith. In each space thus made in the defining-column 14 a figure is produced, and these yfigures read consecutively from 1 to any given figure, and the said defining-column 14 is duplicated at the bottom of the chart, the lower column being designated at 14a. At the left-hand side edge of the chart a vertical designatingcolumn 15 is produced and at the right-hand edge of the charta corresponding designating-column 15a is located. These columns are divided into spaces having figures reading from` the top downward consecutively from fl to any desired number.

Parallel undercut grooves 16 and 17 are produced in the front face of the upper frame member 11, extending from end to end of said ,memben and parallel longitudinal undercut grooves 16a and 17 1 are produced in the outer face of the right-hand side member of the frame, and these latter grooves extend from the upper member 11 out through the bottom kend of the said side member, as is illustrated in Fig. 1. These grooves 16 and 17, 16a and 17EL are of like cross-sectional shape, and they may be '1' shaped in cross-section; but usually they are given a crescent shape. (Shown in Fig. 2.) ln connection with 'the said frame two defining arms orrule'rs C and C extend from the upper portion of the frame to the lower portion thereof, and these Vdefining-arms are preferably made of thin lat metal-for example, steel-and the side edges of the arms are parallel and straight. The body portions of these arms are brought as close as convenient to the outer face of the chart and the upper ends of said arms are curved upwardly and then carried over the outer face of the upper frame member 1l as shown at 18 in the drawings. Each of the said arms or rulers C and C is provided with a slide 19, secured to its under face at its upper end, the said slides having the same cross-sectional shape as the grooves 16 and 17 and 16a and 17a, and said slides for the rulers C and C are made to enter and are adjustable one in the groove 16 and the other in the groove 17. For convenience in moving said larms each arm is provided with a button 20 or its equivalent at its upper end. ln connection with the.arms C and C and crossing the said arms two transverse defining-arms D and D are employed of the same construecio tion as the arms C and C; but the slides of the arms D and D have movement inthe undercut grooves 16EL and 17 1 of the frame.

The free ends of the longitudinal-.slides C and C extend nearly to the linner margin of the lower member of the frame, and the inner ends of the transverse arms D and -D extend practically to the inner edge ofthe left-hand side member 12 of the frame. These arms C `and C', D and D may be plain; but refcrably the arms C and C have a vertica y-reading 'scale of figures in the vertical defining-columns 15 and-15a, while the transverse arms D and D ha ve transversely-reading scales of figures thereon reading the same as the figures in the upper and lower definingcolumns 14 and 14a.

Each slide 19, as is illustrated in Fig. 4, is provided with a downwardly-bowed spring 19EL at its under surface, usually held in posi- 'tion by clips 19h, carried down from the ends of the slides. By means of the said `springs '19 the arms carried by the slides are kept at down 'the figures.

right angles to the frame in which they work and are not easily moved or jarred from place when adjusted.

In the operation of this device, eachpupil being provided with one of said devices and the teacher also with one, the teacher Will set the longitudinal arms at redetermined figures in the upper and in the ower definingcolumns and the transverse arms to certain 'figures in the longitudinal defining-columns 15 and 15, calling out thesefigu're's to the class. rIhe students of the class will then make a corresponding adjustment ofthe said arms upon their charts, and the figures to be added are thus contained within the field bounded by the said arms. Thus an unlimited number of examples can be given out and indicated on the chart without mutilatmg the same and saving the time of dictating the figures and the time of writing In order that the free ends of the defining arms' or rules shall not be in thepway of the user of the device, a guiderod 21 is secured to the frame and is arched over the ends of the longitudinal arms C and C, and a similar rod 22 is arched over the free ends ofthe transverse arms D and D.

I `desire it to be understood that I do not confine myselfito the location of the grooves Vin the frame, as they may be differently placed without departing from the spirit of the invention.

Having thus' described my invention, I claim as new and desire to'secure by Letters Patent- 1. In anl educational device, a chart containing columns of figures, and defining-arms which extend over the chart and are mounted .Y for independent sliding movement, sundry of -themylongituidinally and others transversely relativelyto the said columns of figures.

2 In an educational device, lal chart conthe. said chart, the longitudinal arms from to to bottom and the transverse arms from si e to side.v v

4. In an educational device, a frame the( upper member whereof is providedvwith lun-i dercut grooves in its outer face and the side ,l member with correspondingv grooves, and:

'transverse and longitudinal defining-arms,

each arm being provided with a sprlng-con'- trolled slide at one. end and a knob at the same end, the slides of the longitudinal armsbeing adapted to enter the undercut groovesin the top member ofthe frame and the slides in the transverse arm to enter the undercut grooves in the side member of the frame. 4 6. In an educational device, a frame having undercut grooves in one of its transverse members and corresponding grooves in one of its side members, a chart held in the-said frame, having upper and lower defining-columns reading in consecutive figures com- Inencing with 1,7 and longitudinal marginal defining-columns likewise reading in consecutive figures commencing with "1,Y the bod portion of the chart being provided with co umns in which figures are promiscuously produced,.longitudinal and transverse defining-arms, each defining-arm-being provided with a slide at one end and a knob at the samel end, the slides correspondingA in cross-section to the cross-section of the said grooves, the slides of the longitudinal arms being adjustable in the transverse grooves and the slides of the transverse arms in the longitudinal grooves, the transverse arms extending from side to Vside of .the chart and the longitudinal armsv from top to bottom. thereof, 4the transverse arms havinga scale of figures produced thereon corresponding to the readingof figures in the upper and lower marginal columns and the longitudinal arms having a scale of figures produced thereon corresponding to the figures in the sand mar al columns ofthe chart, and guards for the ree ends ofthe said arms. l

In testimony whereof I have signed my name to this specification in the two subscribing witnesses.

ROY DAVID MITCHELL.

Witnesses:

T.W-BooKMYER, FRANK F. LANGWELL.

IOO

IIO'

presence of v 

